A brief history of underwater construction noise

Abstract

Underwater sound from marine construction became an important issue around the year 2000 because of the potential impacts to marine mammals and fish that are protected by the Endangered Species Act. While protections were in place for marine mammals, there was no guidance for protecting fish. Early on, pile driving was found to visibly injure fish, leading to efforts to reduce sounds, develop protective regulatory thresholds, and research the effects of sound on aquatic species. Over the last 16 years, extensive measurements have been conducted and compiled, protective thresholds have been developed and updated, noise attenuation systems or methods have been improved and tested, and research has been conducted. This paper provides an overview of the different types of sounds characterized, thresholds for protecting animals and the types of noise mitigation strategies employed. Sounds characterized include various types of pile driving in and near water, use of explosives in and near water, mechanical demolition, and dredging-type sounds. The various types of thresholds and methodology for applying those thresholds are discussed. Finally, sounds measured from the various types of attenuation systems are summarized.